Get a program such as DirKey, which integrates with Explorer and the standard Windows Open/Save dialogs, etc. With this you can define a set of folders that you want easy access to. These are activated by hot keys, eg <Shift-Ctrl-1>. You can then have a gesture that sends the hotkey to Explorer.
DirKey from http://www.protonfx.com/dirkey
ps. thanks for the idea. I've been using DirKey via the keyboard and never thought to make a gesture for my favourite folders! ;O)
(The gesture technique hasn't worked for the Open/Save dialgue unfortunately)